Internal-combustion engine lubrication



June 13, 1950 DAUB 2,511,248

INTERNAL-COMBUSTION ENGINE LUBRICATION 6 Sheets-Sheet 1 Original Filed Dec. 27, 1941 INVENTOR H U DC! LPH DALIB AT T DRNEY 6 Sheets-Sheet 2 Original Filed Dec. 27, 1941 INVENTOR R'LIDIJ LPH DAUB ATTEIRNEY 6 Sheets-Sheet 3 Original Filed Dec. 27, 1941 Ill INVENTOR B U A D H P L D D U R ATTEIRNEY u 3, 1950 R. DAUB INTERNAL-COMBUSTION ENGINE LUBRICATION 'e Sheets-Sheet 4 Original Filed Dec. 27, 1941 INVENTOR RUDDLPH D AUB Z /zze/ ATT El R NZY June 13, 1950 R. QAUB INTERNAL-COMBUSTION ENGINE LUBRICATION 6 Sheets-Sheet 6 Original Filed Dec. 27, 1941 INVENTOR. F\' L] DDLF'H DAUE ATTORNEY Patented June 13, 1950 UNITED STATES PATENT OFFICE INTERNAL-COMBUSTION ENGINE LUBRICATION Rudolph Daub, Caldwell, N. J assignor to Wright Aeronautical Corporation, a corporation of New York 3 Claims.

This invention is a division of application Serial No. 424,560 filed December 27, 1941, now Patent No. 2,355,277 and relates to internal combustion engines and in particular comprises a continuing development of the engine design principles disclosed in the application of W. B. Good-man, Serial No. 424,563, filed December 27, 1941 now Patent No. 2,366,852.

In general, an object of the invention is to provide an internal combustion engine assembly in which a very large number of engine cylinders are used in order to secure high power in a single engine unit. A further object of the invention is to provide an aircraft engine of high power in which the components of the engine are so designed and arranged as to secure maximum power output with minimum bulk and weight, an associated object to provide an engine in which the design is as simple, and the components as accessible, as is possible to secure in a power plant of the class here dealt with. A further object is to provide an improved lubrication system for a multi-cylinder engine.

The above objects and further objects will become clear in reading the annexed detailed description of the invention in connection with the drawings, in which:

Figs. 1, 2 and 3 are longitudinal sections through the engine, representing respectively the front, middle and rear portions of the engine;

Fig. 4 is a section through the engine on the central plane through one of the several banks of cylinders;

Fig. 5 is an enlarged longitudinal section through a portion of Fig. 2;

Fig. 6 is an enlarged longitudinal section through a portion of Fig. 1; and

Fig. '7 is a diagrammatic perspective view of the engine lubrication system;

Figure 8 is a schematic view illustrating the gear train drivably connecting each layshaft with a crankshaft and also illustrating the oil flow passage from each layshaft to its associated cam shaft.

Figs. 1 to 6 of the drawings in this case are similar to corresponding views of the drawings in the Goodman application above referred to. The basic engine structure consists briefly of a plurality of tandem arranged polygonal crankcase units the flat faces of these crankcase sections being aligned in a fore-and-aft direction. En bloc cylinder rows are secured to the crankcase faces or decks formed by the built-up crankcase sections whereby the engine may be considered as a multi-bank radial cylinder engine, or as an inline engine having a plurality of radially arranged rows. Each bank of cylinders includes the usual pistons and connecting rods, one of the connecting rods engaging a crankpin of a crankshaft associated with that bank. There are a plurality of crankshafts extending in tandem through the engine and each of these crankshafts is geared to a plurality of high speed layshafts, disposed around the crankshafts and between the skirts of the radially arranged cylinders. The front ends of the layshafts are geared to a central power shaft, coaxial with the crankshaft. Each cylinder row includes an overhead camshaft driven from gears at the front end of the engine which gears also serve to drive certain engine auxiliaries. disposed at the rear end of the engine and are driven from the several high speed layshafts and from one of the crankshafts.

Referring first to Figs. 1, 2, 3 and 4, I show a plurality of crankcase units [6 and H in alternate tandem relation. Secured to the front end of the forwardmost crankcase section [6 is a front crankcase section I8, and secured to the rear end of the rearwardmost crankcase section 16 is a rear crankcase section l9. These crankcase sections are bolted to one another by bolts 20 engaging inturned flanges 2| formed on respective crankcase sections at the diametral planes of the several banks of cylinders. Each crankcase section 16 includes a bearing diaphragm 23 having a main bearing bushing 24 for the center journal 25 of a two-throw crankshaft unit 26. The front journal of said crankshaft unit, as at 21, is borne in a main bearing bushing 28 secured within a bearing diaphragm 29 integral with each crankcase section IT. The rear journal 3| of each crankshaft unit 25 is piloted in a counterbore in the front journal 2? of the next rearward crankshaft in such a manner that adjacent tandem crankshafts may oscillate freely with respect to each other. The rear crankcheek 33 of each crankshaft 26 carries a drive gear 34 which is securely bolted to the cheek, said drive gear lying between the rear face of its crankcheek and the adjacent bearing diaphragm 29. The crankshafts per se are of built-up construction, the center journal 25 and adjacent crankpins 36 and 3! comprising an integral unit, the rear crankcheek 33 being clamp-bolted to the rear crankpin 31 and the front crankcheek 38 being clamp-bolted to the front crankpin 35, said rear and front crankcheeks respectively being integral with the rear and front journals 3| and 21.

Other engine auxiliaries are As indicated above, the several crankcase sections Ii: to Hi are of polygonal exterior form and when assembled comprise exteriorly an elongated polygonal cylinder wherein the polygonal sides comprise cylinder decks, one of these decks being numbered 40. To each deck, an en bloc cylinder row is secured which bridges the built-up crankcase sections, and in the embodiment shown, each cylinder row includes six cylinders 4l preferably of cast material to provide integral coolant jackets 42. Each cylinder carries a liner 43 and in each cylinder is engaged a piston 44 equipped with a piston rod. One piston of a bank is pinned to a master connecting rod 45 having a solid or continuous big end bearing, engaging its associated crankpin 36 or 3'1. Articulated connecting rods 6 connect the remaining pistons of each cylinder bank with the master connecting rod, as is conventional practice in radial cylinder engines. It will be noted that the cylinders of any one longitudinal row are arranged substantially in pairs for instance, the central two cylinders shown are closer to one another than to the cylinder pairs ahead of them or behind them. This spacing of cylinder pairs is to allow for a through passage 48, between them which passage extends from the top of the cylinder block to the cylinder deck 40 drilled at 43 on each side of the bearing diaphragm 29 to allow free communication from the crankcase interior to a camshaft and valve cavity, extended along the top of each row of cylinders, said cavity being established by a cylinder cover 50 secured to suitable flanges 41 integral with the cylinder jacket castings.

Between the sleeves 43 of the cylinders are disposed layshafts parallel to the crankshaft These layshafts as shown in Fig. 2, comprise tandem sections whose ends are splined to sleeves 52 which are borne in bearings 53 secured to the diaphragms 29. Integral with each sleeve 52 is a pinion 54 which engages one of the crankshaft gears 34. The front end of the front layshaft 5! is carried in a bearing in the diaphragm 55 at the front of the crankcase section [8 and carries an integral drive pinion 56 borne in an outboard bearing 5] in an auxiliary diaphragm 58 secured to the crankcase. A small pinion 5a is formed at the extreme front end of the front section of each layshaft 51, this pinion driving a compound idler gear 66, in turn driving an idler gear 6!, an idler gear 62, and a camshaft gear 63, all of which are journalled in the diaphragm 58. There is one gear train 59, 66, 6|, 62, and 63 for each layshaft 5i and for each row of cylinders, said gear trains are not exactly radial so that a single complete gear train is not visible in Figure 1. As shown in Fig. 1, one of the idler gears such as 62 may be used to drive an engine auxiliary such as a magneto 65, to serve the adjacent cylinder row, through a shaft 66 secured to the crankcase nose section 61. If the engine is of the fuel injection type, a fuel injector unit 53, to serve the adjacent cylinder row, may be driven from each camshaft gear 63. The magneto and fuel injector of each cylinder row serves that cylinder row and may be timed perfectly in accord with piston positions of that row. This arrangement avoids the timing inaccuracies common to usual radial engines having master and articulated connecting rods wherein the magnet-0s are driven from the crankshaft and serve all cylinders of a radial bank. In this engine, one magneto serves all master rod cylinders, and another magneto serves each aligned row of articulated rod cylinders.

As shown, the engine may be considered as a six bank radial engine having seven cylinders per bank, or alternately, as an in-line engine having seven radial rows of six cylinders each. The number of cylinders in each bank or in each row may be changed as desired. For instance, each row might have four cylinders, and the center crankshaft unit would be eliminated, giving a 28 cylinder engine.

To the front crankcase diaphragm 55, a bearing member 78 is secured which forms an oil transfer bearing cooperating with the rear end of a propeller shaft 'H at the extreme rear end of which is a journal 12 piloted in the bearing in the front end of the front crankshaft. Said propeller shaft 1| is further carried in a thrust bearing 73 and a radial bearing 14 at the front end of the crankcase nose section 61. Piloted on a bushing i5 associated with the oil transfer bearing in the member '10 is an intermediate gear 16 meshed with the several layshaft pinions 56. Said gear includes inclined annularly arranged pockets l8 opposite similar annularly arranged inclined pockets 19 in an axially shiftable member 80, there being a plurality of rollers 31 between said pockets to transfer torsional driving effort from the gear '16 to the member 80 while at the same time creating an axial force between said members which is proportional to the torque transmitted. A cylinder 82 is formed in the member 80 which is engaged by a piston 83 rigid with the bushing 75 and with the gear 16. Fluid under pressure is admitted to the cavity between the piston and cylinder through the oil transfer bearing in the member 10 to counteract the axial thrust caused by transmitted torque. Pressure of the hydraulic fluid in the cylinder 82 will thus be proportional to torque transmitted and this pressure is registered on an appropriate gauge. As pressure builds up in the cylinder 82, it will be moved axially relative to the piston, until the latter uncovers a bleed port 82 in the cylinder rim to establish a pressure proportional to the torque transmitted. A centrifugal balance cell 84 is formed between the member 80 and a portion of the hub of the gear 16, to which oil bleeds from, the cylinder 82. This cell is vented close to its most radial-1y inward point, so that, during rotation of the system the centriufgally produced oil pressures in the cell 84 and in the cylinder 8,2 are-balanced and thus, do not affect torqueproportional pressure in the cylinder 82. The member 80 carries a gear 85 meshed. with a plurality of gears 86 on, layshafts 81 journalled in bearing members 88. and 89 secured to. the crankcase nose section 6'! by bolts 90. Said, layshafts carry pinions 9i meshed with a ring g ar 92 secured at a spline compe ition, 93, to the propeller shaft 'II. It will be noted that said shaft comprises, rearward and forward portions which are secured to one another in the region of the spline connection 93. The members 88 and 89 define, with the crankcase nose section 61, an annular oilduct 94 serving asa distributor, as will become apparent.

When changes in the reduction gear ratio, or a dual propeller shaft or a two speed propeller drive are desired, these matters may be taken care of by altering the gears and elements 36', 81, 88', 89, 9| and 92, as a, bench assembly, separate from the engine per se, and installed as a unit in the nose section. Furthermore, the torque meter remains intact with the engine and, since it is disposed between the engine and reduction gear, al-

ways indicates true engine torque regardless of the reduction gear ratio.

Immediately rearward of the plane radial bearing it is a bevel gear 95, secured to the propeller shaft, which gear serves to drive an oil pump unit 96 and a propeller governor unit 91, both of said units being secured to the crankcase nose section 6?.

Referring now to Fig. 3, the rear crankcase section It carries a bearing member 28 in which the rearmost layshaft pinion is journalled. The pinion 5 3, as before described, has a spline connection with the rear layshaft 5 I. The sleeves 52 of one or more of the rear pinions 5-; are splined to a short shaft 3% splined to a gear I06 borne in bearings in a rear crankcase bearing member I ill and in a front supercharger housing member IE2, th latter being secured as at Ills to the rear crankcase I9. Idler gears I64 are carried by the housing I32, which are driven by the gears led and which drive the supercharger impeller shaft gear 35, the impeller shaft with which said gear is integral being designated I66 and having splined thereto a supercharger impeller It's. The shaft N33 is piloted upon a rear crankshaft extension I38 whose front end is splined to the rear cheek of the rear crankshaft at let. The rear end of the shaft I08 is splined to a, starter drive dog I Ill secured in a crankcase accessory section iii. Said shaft I 53 carries a gear I [2 on its rear end meshed with a plurality of gears IIS on layshafts II l which comprise power takeoffs for various engine auxiliaries such as generators, tachometer drives, and oil pumps, an oil pump unit being shown at H5.

It will be noted that the rear crankshaft extension we is at the same end of the rear crankshaft as its power gear 34, insuring smooth torque to the accessory drives, uninfluenced by torsional wind-up in the crankshaft. In the usual engine, power is taken from one end of the crankshaft while accessories are driven from the other, unbalancing the phase relation therebetween due to variations in angular deflection between the crankshaft ends caused by torque variations.

In this engine, direction of rotation may be reversed merely by changing the camshafts, the supercharger impeller and diffuser, and altering the drive gearing in the accessory section to allow accessories to rotate in the same direction as before the change was made. The accessory section chan e would consist in adding an idler gear between the gears I I2 and I I3.

The rear oil pump unit includes a pressure pump and a scavenging pump, the former delivering pressure oil through a suitable conduit in the crankcase sections, not shown, to a pressure oil annulus I I3 integral with the front supercharger housing 162, said annulus passing across the rear ends of the several layshafts 5|, said layshafts being hollow. The short shafts 99 preferably are also hollow whereby oil under pressure is transmitted from the annulus II6 through the shafts 99 as well as through the spaces between the splines of the shafts 99 with layshafts 5| and said oil passes forwardly along the layshafts which are provided at appropriate intervals with openings communicating with holes in bearing bushings which in turn communicate with oil passages such as H8 leading to the main crankshaft bearings of the engine. Said main crankshaft bearings in turn are drilled to conduct oil to the crankshaft interiors whence oil is conducted to the 'crankpin bearings for lubrication of the connecting rod bearings, knuckle pin bearings and pistons in the usual manner. Referring briefly to Fig. 1, it will be noted that the front section of the layshafts 5| are provided with drillings to lubricate certain of the reduction gear bearings and, through suitable crankcase passages, such as schematically indicated at 94' in Figure 7, pressure oil is led from the layshaft head or front ends to the distributing annulus M and thence to sundry bearings of the reduction gear and nose section.

Figures 1 and 6 show one of several similar oil passages I 29, fed from the layshaft, each said passage I29 communicating with an annular groove ill in a layshaft bearing 5'! and thence with the interior of its associated layshaft through radial holes H9. Each passage I20 passes across the journals for the several camshaft idler gears 68, III and 62 for one cylinder row, for lubrication thereof, to the bearing for the camshaft gear 63. The passages I23 are schematically illustrated in Figures 7 and 8. This bearing with associated parts comprises an automatic pressurereducer to admit oil to the hollow camshaft I2I at a pressure less than full pump pressure. To this end, drillings I23, I25, and I25 are formed in the several bushings and hub elements of the camshaft gear, the drilling I25 being in the camshaft I2I and forming a port which cooperates with an axially slid'able valve I 2Bnormally urged to the right by a spring I27. Said sleeve includes radial drillin s I28 which may at times register with drillings I25 to allow of oil entrance into the hollow camshaft. When the oil pressure within the camshaft increases, the valve I26 will move to the left under the influence of said pressure, against the spring I27, to throttle the drilling I25 and to maintain within the camshaft an oil pressure established by the strength of the spring I27. The purpose of this reduction in oil pressure to the camshaft is to control oil flow and to avoid excessive oil bleed from the pressure system, since the lubrication requirements for the valve gear are small. There is a similar system for each camshaft and for each cylinder row.

In a diagramatic representation of the lubrication system in Fig. 7, this oil pressure reducer is designated I 26. Another pressure reducing valve I29, shown in Fig. '7, is arranged between the oil pump H5 and a, low pressure oil feed annulus I38 in the accessory drive section III (Fig. 3), this annulus serving as an oil header for the lubrication of the several accessory drive gears.

Referring to Figs. 2 and 4 it will be seen that each camshaft I2I extends the full length of each cylinder row and is journalled in a lower bearing half I3I formed in the head of each cylinder and carrying a suitable half bushing. The bearing cap I32 which secures the camshaft to the bearing half ISI is bolted to the cylinder head and comprises a unitary fitting which includes two sets of rocker bearings I34 axially parallel to the camshaft and spaced above and to either side of the camshaft. These bearings carry rocker arms I35 having rollers I36 engaged with the camshaft and having adjustable elements I 31 for engagement with the tops of valve stems I38. This unitary bearing cap and rocker carrier I32 avoids the use of many small parts and affords easy assembly and disassembly of the rocker system and of the camshaft assembly. There is one cap and rocker assembly I32 for each cylinder head and it will be noted that bending deflections in the camshaft are minimized by having a camshaft bearing between each pair of cams and rocker arms. The valves I38 are carried in valve guides, in the cylinder head in the conventional manner, as shown in Fig. 4, and their heads engage inserted valve seats at the top of each combustion chamber.

While I have described by invention in detail in its present preferred embodiment, it will be obvious to those skilled in the art, after understanding my invention, that various changes and modifications may be made therein without departing from the spirit or scope thereof. I aim in the appended claims to. cover all such modifications and changes.

I claim as my invention:

1. In an engine including a crankshaft and a, hollow camshaft; a lubrication system therefore comprising an oil pump operable to supply oil under full pump pressure to the crankshaft bearings, passage means for supplying oil from said pump to the. hollow camshaft and thence to the camshaft bearings, and valve means co-axial with said hollow camshaft for controlling the admission of oil therein, said valve means being arranged to automatically move in a closing direction in response to an increase in the oil pressure within said camshaft.

2. In an engine including a crankshaft and a hollow camshaft; a lubrication system therefore comprising an oil pump operable to supply oil under pressure to the crankshaft bearings, a passage for supplying oil from said pump to the hollow camshaft and thence to camshaft bearings, a valve for controlling the admission of oil into said hollow camshaft, and a spring for urging said valve in a direction for opening said passage, said valve bein arranged to automatically move in a closing direction in response to an increase in oil pressure within said camshaft.

3. In an engine including a crankshaft; a lubrication system therefore comprising an oil pump operable to supply oil under pressure to the crankshaft bearings, a passage for supplying oil from said pump to other bearing surfaces of said engine, a valve controlling the flow of oil through said passage to said bearing surfaces, and a spring for urging said valve in a direction to open said passage, said valve being urged against said spring in response to the oil pressure on the downstream side of said valve.

RUDOLPH DAUB.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,266,288 Loomis May 14, 1918 1,381,150 White June 14, 1921 1,427,190 Brown Aug. 29, 1922 1,622,172 Angle Mar. 22, 1927 1,676,418 Vincent July 10, 1928 1,690,030 Noble Oct. 30, 1928 1,815,868 Schenk July 21, 1931 1,897,191 Farina Feb. 14, 1933 1,900,968 Woolson Mar. 14, 1933 1,975,826 Codrington Oct. 9, 1934 2,043,529 Davis June 9, 1936 

